1. Field of the Invention
This invention relates to throttle control in vehicles, and more particularly to systems that prohibit unintended acceleration in vehicles.
2. Description of the Related Art
One typical system for control of a vehicle's engine throttle in modern vehicles is illustrated in FIG. 1 and shown schematically in FIG. 7. An Electronic Control Module (“ECM”) 101 (referred to as “the car computer”and alternatively as “ECU”), illustrated as a microprocessor, receives electronic inputs from vehicle components such as the vehicle's transmission, cruise control, power steering, air conditioner, load (manifold absolute pressure (MAP), traction control, etc) and other remotely sent signals for processing and further component control, and may provide a voltage reference for such components. The ECM 101 also receives information indicating the position of the vehicle's accelerator pedal 114 through pedal input sensor 113. As is typical for motor vehicles, the accelerator pedal 114 enables driver control of the vehicle's motor, from engine idle to full throttle.
The ECM 101 is electrically connected to an Electronic Throttle Control Motor (“ETCM”) 105 in a throttle body assembly (“TB”) 112 to provide “drive-by-wire” electronic throttle control of the vehicle's motor. The ETCM 105, typically an electric motor, actuates a throttle plate 115 (represented by dashed lines) in the TB 112 that acts as a variable valve to control the amount of air flowing into the vehicle's motor for throttle control from idle to full throttle positions. Also connected to the ECM 101 is a throttle position sensor (“TPS”) 103 in the TB 112 to provide engine throttle plate position feedback to the ECM 101. The TPS 103 converts physical position of the throttle plate within the TB 112 to an electrical signal for throttle feedback to the ECM 101. The TPS 103 includes a potentiometer 108, which provides a resistance, and wiper arm 107. Wiper arm 107 is in communication with the throttle plate 115. Potentiometer 108 is connected between lines 110, 111, and wiper arm 108 is connected to line 109. Line 110 is reference to ground. Lines 109, 110, 111, are connected to ECM 101.